Primary care interventions linked to increase in moderate, vigorous physical activity

Physical activity interventions in primary care may increase patients' weekly moderate- to vigorous-intensity physical activity, a recent systematic review and meta-analysis found.

Researchers reviewed 51 randomized controlled trials that assessed aerobic-based physical activity interventions delivered or prompted by health professionals in primary care and included a control group. Most of the trials were conducted in the U.S. and had primary care clinicians deliver the interventions. Twenty-three interventions were delivered in multiple brief sessions, 18 were intensive, and 10 were brief. The primary outcome was the difference between groups in moderate- to vigorous-intensity physical activity (measured in minutes per week) from baseline to final follow-up. The researchers also assessed the odds of meeting WHO guidelines for moderate- to vigorous-intensity physical activity at follow-up. Results were published Feb. 23 by The BMJ.

The meta-analysis included 46 randomized controlled trials with 16,198 adult participants and follow-up ranging from one month to five years. Overall, physical activity interventions delivered or prompted by health professionals in primary care increased moderate- to vigorous-intensity physical activity by an average of 14 minutes per week (95% CI, 4.2 to 24.6 min/wk; P=0.006), although heterogeneity between studies was substantial (I²=91%; P<0.001). When analyses were limited to trials that used a device to measure physical activity, there was no significant between-group difference in moderate- to vigorous-intensity physical activity (4.1 min/wk [95% CI, −1.7 to 9.9 min/wk]; P=0.17), with an I² of 56% (P=0.008).

Trials that used self-report measures showed that intervention participants engaged in 24 minutes per week of moderate- to vigorous-intensity physical activity compared to controls (95% CI, 6.3 to 41.8 min/wk; P=0.008), with an I² of 72% (P<0.001). In addition, interventions increased the odds of patients meeting guidelines for moderate- to vigorous-intensity physical activity (odds ratio, 1.33 [95% CI, 1.17 to 1.50]; P<0.001) versus controls, with an I² of 25% (P=0.11). Although 14 of 46 studies had high risk of bias, excluding them in sensitivity analyses did not alter the results.

Self-reported measures might overestimate physical activity, among other limitations, the study authors noted. They added that in some trials, usual care included brief physical activity advice from a primary care health professional, which could have affected the results.

Regarding this limitation, the reported increase of a modest 14 minutes per week may be an underestimate, and the weighted average could obscure substantial variation between individuals, an accompanying editorial noted. Nonetheless, the findings provide evidence to support physical activity interventions in primary care, the editorial said.

“Future research should focus on identifying the most effective interventions, optimising outcomes for all population groups, and evaluating how best to decrease sedentary time as well as increasing physical activity,” the editorialists wrote.